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Re: [PATCH] sha1_file: avoid comparison if no packed hash matches the first byte

From
Jeff King <peff@peff.net>
Date
Aug 8, 2017, 22:58 UTC
Message-ID
<20170808225851.kgbyrlqrtlurzc73@sigill.intra.peff.net>
In-Reply-To
<20170808225231.3l7gyoxxvghsvtv7@sigill.intra.peff.net>
On Tue, Aug 08, 2017 at 06:52:31PM -0400, Jeff King wrote:
Show 8 quoted lines
> > Interesting.  I see that we still have the conditional code to call
> > out to sha1-lookup.c::sha1_entry_pos().  Do we need a similar change
> > over there, I wonder?  Alternatively, as we have had the experimental
> > sha1-lookup.c::sha1_entry_pos() long enough without anybody using it,
> > perhaps we should write it off as a failed experiment and retire it?
> 
> There is also sha1_pos(), which seems to have the same problem (and is
> used in several places).

Actually, I take it back. The problem happens when we enter the loop with no entries to look at. But both sha1_pos() and sha1_entry_pos() return early before hitting their do-while loops in that case.

-Peff
Previous: Jeff KingNext: Junio C Hamano
Message 5 of 14 in “sha1_file: avoid comparison if no packed hash matches the first byte”
  1. sha1_file: avoid comparison if no packed hash matches the first byteRené Scharfe, Aug 8, 2017
  2. Jonathan NiederAug 8, 2017
  3. Junio C HamanoAug 8, 2017
  4. Jeff KingAug 8, 2017
  5. Jeff KingAug 8, 2017
  6. Junio C HamanoAug 9, 2017
  7. Jeff KingAug 9, 2017
  8. Jeff KingAug 9, 2017
  9. 1/2 sha1_file: drop experimental GIT_USE_LOOKUP searchJeff King, Aug 9, 2017
  10. Junio C HamanoAug 9, 2017
  11. Jeff KingAug 9, 2017
  12. 2/2 hashcmp: use memcmp instead of open-coded loopJeff King, Aug 9, 2017
  13. René ScharfeAug 9, 2017
  14. Jeff KingAug 9, 2017

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